Some types of instrumentation systems involve the interfacing of a plurality of inputs from multiple transducers and other input sources. To address these circumstances, the Institute of Electrical and Electronics Engineers (IEEE) Standards Association has developed a standard for interfacing multiple, physically separated transducers that allows for the time synchronization of data, known as IEEE 1451.3 “Standard for a Smart Transducer Interface for Sensors and Actuators, Digital Communication and Transducer Electronic Data Sheet (TEDS) Formats for Distributed Multidrop Systems.” In brief, the standard attempts to provide a minimum implementation for the self-identification, multidrop, hot swapping and configuration of transducers in such instrumentation systems and networks.
For example, FIG. 1 is a multidrop instrumentation system 100 as contemplated by the IEEE 1451.3 standard. The system 100 includes a first transmission line 102 coupled between a Transducer Bus Controller (TBC) 104 of a Network Capable Application Processor (NCAP) 108 and a plurality of Transducer Bus Interface Modules (TBIM) 106. The first transmission line 102 is used to supply power to the TBIMs 106 and to carry communication signals between the TBIMs 106 and the bus controller 104. A second transmission line 103 serves as a network communications channel and is used to establish the basic network communications that allows the bus controller 104 to determine the capabilities and configuration of each TBIM 106. This portion between the TBIMs and TBC is considered the physical layer of the system. In turn, the NCAP 108 is coupled to a network 110, and contains the bus controller 104 and an interface to the network 110 that may support many other buses. Each TBIM 106 may contain one or more different transducers or other signal generators.
Although desirable results have been achieved using such systems, the IEEE 1451.3 standard may not be reliable or suitable for some types of distributed multidrop transducer systems and networks.